A typical coffee whitener formulation is described in The Journal of American Oil Chemical Society, 46, J. H. Hetrick, 1969, having the following composition:
______________________________________ Vegetable fat 6-12% Sweetening agents (sugar, 4- 10% (solids, basis) Corn syrup solids, corn syrup) Protein .75-1.5% Emulsifier 0.2-1.0% Buffer 0.1-0.5% Stabilizer 0.02-0.15% ______________________________________
the remainder being water. A similar formulation is described in prior U.S. Pat. No. 3,563,761, the protein being sodium caseinate.
As pointed out in the '761 patent, the sodium caseinate serves the function in a fat/water emulsion of encapsulating the fat globules, as a film former, and binding water, thus stabilizing the emulsion and preventing oil/water separation.
Sodium caseinate, however, is in short supply and its use in food compositions adds substantially to the cost of such compositions. In addition, it is necessary when using a protein such as sodium caseinate, to also add a buffer to prevent "feathering" of the protein. Most coffees have a low pH near the isoelectric point of the protein which causes the protein to coagulate when the whitener is added to the coffee, in turn resulting in a breakdown of the emulsion. The buffering salts hydrolyze to slightly basic solutions, increasing the pH to above the isoelectric point.
Common, acceptable buffers are disclosed in prior U.S. Pat. No. 4,092,438 and include such phosphate salts as dipotassium phosphate and certain citrate salts.
Many recent developments have been made directed to the problems of emulsion stability and feathering in coffee whiteners. In addition to the two patents mentioned above, reference can be had to the following representative U.S. Pat. No.:
3,695,889 (Avoset) is on the use of an emulsifier blend comprising polysorbate 60, sodium stearoyl-2-lactylate, and propylene glycol monostearate in a buffered/caseinate product.
3,712,865 (Lever Bros.) describes acylating protein in oil-in-water emulsions. This patent, as with the '761 patent, discusses the importance of protein to provide an interface and prevent oil droplet coalescence.
3,958,033 (General Foods) describes a protein-free, nonhomogenized emulsion containing nearly 50% sugar, about 25% water, and about 25% lipid including fat and an emulsifier blend comprising a lactylate or fumarate salt, or succinylated monoglyceride, alone, or in combination with an adjunct emulsifier such as propylene glycol monostearate.
4,025,659 (Ralston-Purina Co.) describes a coffee whitener composition containing soy protein isolate which is said to exhibit substantial resistance to feathering or oil separation in hot coffee, provided the soy is used in combination with caseinate.
4,045,589 (Carnation Co.) describes a coffee whitener which is protein-free but which contains a chemically modified dextrinized starch having a lipophilic character.
4,046,926 (General Foods Ltd.) describes a non-dairy creamer composition based on sodium caseinate and containing effective amounts of sodium carbonate and a phosphate or citrate for what is said to be improved resistance to feathering.
In all of the above patents except 3,958,033 and 4,045,589, caseinate or other protein is considered an essential ingredient. Only in the two exceptions is there described a composition which is protein-free. In the '033 patent, the composition disclosed is one which is very viscous and obtaining a stable emulsion would not be difficult. Contributing to the viscosity is a large amount of sugar and a consumer could well find the sweetness level to be objectionable. The fat level also would tend to make the formulation representative of a rich cream rather than a conventional coffee whitener. Similar disadvantages exist with regard to the '589 patent.